"IRWIN" SPEEDBOR MAX BORING BIT SET *Set includes the following sizes: 5/8", 3/4" and 1" *Fits all standard 1/4" quick change chucks and for use with drills up to 1/2" shank *Tri-flute design for faster chip removal *3 cutting spurs for clean holes with minimal "breakout" *Six times faster than standard spade bits *Screw tip fully heat treated *Hex shank for quick change applications. *Tri-flute design for faster chip ejection *Full screw tip for ease of use and pull through*Cutting spurs for clean holes *Discovery CON, NBR, SUP